[erlang-questions] My quest for a decent way to make a GUI in erlang

[Joe Armstrong]

More on my search for a good (understandable) GUI engine...

I've spent the last few weeks botanising through various
GUI/graphics construction kits - and goodness what a mess.

I thought I'd share some of my experiences and see if
it resonates with anybody.

1) Gui building is an (almost) total mess - I say almost because
   there is some good software around - but the good stuff tends to be
   experimental, undocumented and difficult to use.

2) The most popular frameworks are bloated, difficult to use and
   impossible to understand without significant effort.

3) wxWidgets and the Erlang port wxErlang is usable - but the
   documentation assumes you are familiar with the wxWidgets way
   of doing things and with OO callback programming - which is
   *very* Un-Erlang way of thinking

4) The use of interface builders (Xcode, etc.) is a symptom of
   problem. GUI codes gets so messy that it is virtually impossible
   to write "by hand" - so enter the GUI builder - this is basically
   giving up on the idea that GUIs can be written in a clear and
   simple manner by hand.

5) In the late 1970 - mid 80's there were several GUI languages
   and systems that were easy to use and easy to program. For
   example Smalltalk, TCL, Visual basic, Borland Turbo Graphics

Is there any good stuff around today?

Surprisingly the answer is yes - but the code is difficult to find
not supported and not mainstream.

First a couple of papers that you might find interesting:

   + http://www.eugenkiss.com/projects/thesis.pdf
     and https://github.com/eugenkiss/7guis/wiki

    The author solves 7 different problems with a number of different
    GUI's

   + http://blog.johnnovak.net/2016/05/29/cross-platform-gui-trainwreck-2016-edition/

   A great read - This blog has a lot of good information about the techniques
   used to build several state of the art GUIs (for example Reaper,
Blender, Light table)
   so If you've every wondered how fancy GUIs work this article gives
several clues.

   It also has the rather nice example of a GUI written using the
Electron Framework
   that made an 189 MB executable to bang up a window with a small number of
   controls in it.

   There's a list of references in one of the comments to this blog that
   lead to several interesting *small'ish GUIs'

Good stuff

   I did find some good software and some potentially very good software.
   My top picks are as follows:

   http://inscore.sourceforge.net/

      This is my favorite from an architectural POV.
      It is controlled entirely by sending it messages.
      Not a single callback to be seen

   https://github.com/andlabs/libui

      This looks very promising - it's a cross platform adaption layer
      with a C interface - I've only build it on a Mac but
      the adaption layer looks pretty easy to use. There's a C interface
      that could be adapted to Erlang.

      There are very few examples
https://github.com/andlabs/ui/wiki/Getting-Started
      has a go example - but if you download and build the system the
      C examples are easy to follow.

   http://www.red-lang.org/

      Is amazing - Red is a language inspired by REBOL.

      REBOL never achieved much popularity - perhaps Red will.
      Once you've see red you'll wonder why you program in anything else
      (there are good reasons - but for simply desktop apps Red is great).

   https://github.com/wjakob/nanogui

      Restores my faith in programming - it's small and built on top
      of https://github.com/memononen/NanoVG

      NanoVG is basically a canvas type interface to OpenGL

      Reading the NanoGui code made me wonder if the best way to make
      a GUI for erlang would be to use OpenGL for the low-level stuff
      and do all the rest in Erlang.

      Buttons etc. are pretty easy to define as processes which I believe
      is the way http://www.wings3d.com/ did things.

The future

I'm still undecided - one of more of the following seem attractive

    1) wxErlang - it works *but* it's big and ugly and has a nasty
       programming model
    2) An interface to Red would be great - but red is pretty unknown
    3) libui looks promising - anybody interested in this?
    4) the nanogui/NanoVG track looks good - anything with nano in the
       name has my vote
    5) The inscore architecture rules - NO CALLBACKS - Yea

Verily verily I say unto you - "useth not the callback, even though
they that useth the callback are ignited with a great passion and
extol the virtues of the callback - for therein lies the madness
that do come when the callback faileth for reasons not comprehended'

Thus it is writ.

Cheers

/Joe